Apparatus for recording and/or reproducing information and/or from optical information record disk

ABSTRACT

An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each other in accordance with said position signal and rotation signal.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an apparatus for recordingand/or reproducing information on and/or from an optical record diskcomprising an optical head including a semiconductor laser for emittinga laser beam, an objective lens for projecting the laser beam emitted bythe semiconductor laser onto the optical information record disk and aphotodetecting means for receiving a return laser beam reflected by saidoptical information record disk to produce information signal andfocusing error signal; a disk driving device including a turntable forsupporting the optical information record disk and s spindle motor forrotating said turntable together with the optical information recorddisk; means for driving at said objective lens in a radial direction ofthe optical information record disk; and a control means for performinga focus control for moving said objective lens and turntable relative toeach other for moving a relative position of a focus point of the laserbeam with respect to the optical information record disk in a focusingdirection which is parallel with an optical axis of said objective lens.

[0003] 2. Related Art Statement

[0004] In Japanese Patent Application Publication No. 1-35415 publishedon Jul. 25, 1989, there is described a known apparatus for recordingand/or reproducing information on and/or from an optical informationrecord disk such as the magneto-optical record disk. In this knownapparatus, when the cartridge having an optical disk installed thereinis inserted into the apparatus, the cartridge is inserted into a holderof a cartridge loading mechanism and this holder is movably arranged ona driving member, and when the cartridge is fully inserted into theholder, the driving member is moved downward so that the optical disk isplaced on a turntable which is coupled with a driving shaft of a spindlemotor. In this apparatus, the optical disk can be place on the turntablewithout moving the spindle motor and turntable up and down, so that thedisk driving device may be simple in construction. However, the holderhas to be moved not only horizontally, but also vertically, andtherefore the mechanism for driving the holder is liable to becomplicated and a stable operation could be hardly attained.

[0005] In order to avoid the above mentioned drawbacks, there has beenproposed another known apparatus described in Japanese PatentApplication Laid-open Publication Kokai Hei No. 4-321972 published onNov. 11, 1992. In this known optical information record disk apparatus,after a cartridge having a magneto-optical record disk installed thereinis inserted into the apparatus, a spindle motor for rotating the opticaldisk is moved upward such that the optical disk is supported by aturntable provided on a driving shaft of the spindle motor. In thisknown apparatus, it is no more necessary to provide a mechanism fordescending the cartridge in the cartridge loading mechanism, and thusits construction becomes simple and small. Further, in this knownapparatus, a focus control including focus search and focus servo isperformed by moving the spindle motor, turntable and optical disk in adirection parallel with an axis of the spindle motor such that adistance between the objective lens and the information record plane ofthe optical disk is changed. Therefore, it is no more necessary toprovide, in the optical head, an objective lens driving mechanism formoving the objective lens in a direction of its optical axis and thusthe optical head can be made small in size and light in weight. Itshould be noted that the Focus servo control means a control foradjusting a distance between the objective lens and the optical disk inaccordance with a focusing error signal by means of a focus servomechanism so that the light beam is correctly focused on the opticaldisk, and the focus search control means a control for setting saiddistance within a controllable range of the focus servo mechanism.

[0006] In this known apparatus, the spindle motor is secured to anup-down block, and turntable and cartridge positioning member aresecured to the up-down block. When the up-down block is moved upward, alower surface of the cartridge is supported by projections of thecartridge positioning member and an optical disk installed within thecartridge is supported on the turntable. The disk is firmly secured ontothe turntable by means of a permanent magnet. The up-down block is movedup and down by a cum mechanism including a cum gear and a up-down motorfor rotating the cum gear by means of a gear box, a cum surface of saidcum gear being engaged with a roller arranged rotatably on a sidesurface of the up-down block. A rotation of the cum gear is detected bya rotary encoder, so that a position of the up-down block can bedetected by processing an output signal of the rotary encoder.

[0007] In this known apparatus, the position of the up-down block is notdirectly detected, but is presumed from the rotation of the cum gear. Bysuch an indirect detection, the position of the up-down block could notbe accurately detected owing to the reason that the gears contain backrush and thus the output signal detected by the rotary encoder could notprecisely represent an amount of the actual up-down movement of theup-down block. It should be noted that the focus control including thefocus search and focus servo has to be performed in relation to aposition of a movable portion including the up-down block, turntable,cartridge positioning member and spindle motor, but in the knownapparatus the position of the movable member could not be detectedprecisely and it is no more possible to perform the focus controlprecisely.

[0008] Further, in the known disk driving device, substantial parts ofthe device including the up-down block, spindle motor, turntable andcartridge positioning member are moved up and down, and thus arelatively heavy load is applied to the up-down motor. Therefore, theup-down motor is liable to be large. Moreover, during the focus control,not only the turntable, but also the up-down block and spindle motor aremoved up and down, the projections of the cartridge positioning membermight vibrate and thus the projections might hit the cartridge toproduce annoying noise.

SUMMARY OF THE INVENTION

[0009] The present invention has for its object to provide a novel anduseful apparatus for recording and/or reproducing information on and/orfrom an optical information record disk, in which the position of theup-down block can be detected precisely, so that the focus control canbe carried out accurately and reliably.

[0010] It is another object of the invention to provide a novel anduseful apparatus for recording and/or reproducing information on and/orfrom an optical information record disk, in which the focus control canbe performed without moving the up-down block and spindle motor, so thatthe focus control can be effected accurately.

[0011] It is still another object of the invention to provide a noveland useful apparatus for recording and/or reproducing information onand/or from an optical record disk, in which a focus control can beinitiated stably and reliably.

[0012] According to the invention, an apparatus for recording and/orreproducing information on and/or from an optical record disk comprises:

[0013] an optical head including a semiconductor laser for emitting alaser beam, an objective lens for projecting the laser beam emitted bythe semiconductor laser onto the optical information record disk and aphotodetecting means for receiving a return laser beam reflected by saidoptical information record disk to produce information signal andfocusing error signal;

[0014] a disk driving means including an up-down block arranged movablyin a direction perpendicular to a plane of the optical informationrecord disk between a lower position and an upper position, an up-downmotor for moving said up-down block between said lower position andupper position, a turntable for supporting the optical informationrecord disk and a spindle motor secured to said up-down block and havinga driving shaft coupled with said turntable for rotating the turntabletogether with the optical information record disk;

[0015] an optical head driving means for driving at least said objectivelens in a radial direction of the optical information record disk;

[0016] a position detecting means for detecting directly a position ofsaid up-down block to derive a position signal when the up-down block isdriven into said upper position;

[0017] a rotation detecting means for detecting a rotation of saidoptical information record disk to derive a rotation signal when theoptical information record disk is rotated at a predetermined revolvingspeed; and

[0018] a control means for initiating a focus control for moving saidobjective lens and turntable relative to each other in accordance withsaid position signal and rotation signal.

[0019] According to a preferable embodiment of the apparatus accordingto the invention, said turntable of said driving means is arranged on adriving shaft of said spindle motor such that the turntable is rotatedtogether with the driving shaft but is slidable along the driving shaft,and said disk driving means comprises a first driving device for movingthe up-down block up and down and a second driving device for movingsaid turntable up and down along the driving shaft of the spindle motor.

[0020] According to further aspect of the invention, an apparatus forrecording and/or reproducing information on and/or from an opticalrecord disk comprises:

[0021] an optical head including a semiconductor laser for emitting alaser beam, an objective lens for projecting the laser beam emitted bythe semiconductor laser onto the optical information record disk and aphotodetecting means for receiving a return laser beam reflected by saidoptical information record disk to produce information signal andfocusing error signal;

[0022] a disk driving means including an up-down block arranged movablyin a direction perpendicular to a plane of the optical informationrecord disk between a lower position and an upper position, an up-downmotor for moving said up-down block between said lower position andupper position, a turntable for supporting the optical informationrecord disk and a spindle motor secured to said up-down block and havinga driving shaft coupled with said turntable for rotating the turntabletogether with the optical information record disk;

[0023] an optical head driving means for driving at least said objectivelens in a radial direction of the optical information record disk;

[0024] a position detecting means for detecting directly a position ofsaid up-down block to derive a position signal when the up-down block isdriven into said upper position;

[0025] a control means for initiating an energization of said spindlemotor for rotating the optical information record disk in accordancewith said position signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a half cross sectional and half front view showing anembodiment of the disk driving means of the optical informationrecording and/or reproducing apparatus according to the invention;

[0027]FIG. 2 is a schematic view depicting a whole construction of theapparatus;

[0028]FIG. 3 is a plan view representing the objective lens drivingunit;

[0029]FIG. 4 is a perspective exploded view illustrating the objectivelens driving unit;

[0030]FIG. 5 is a flow chart explaining the operation of the apparatus;

[0031]FIG. 6 is a side view showing another embodiment of the diskdriving device according to the invention;

[0032]FIG. 7 is a side view of the disk driving device of FIG. 6 in acondition in which the cartridge is not fully inserted;

[0033]FIG. 8 is a side view illustrating a modification of the diskdriving device shown in FIG. 6;

[0034]FIG. 9 is a cross sectional view depicting another embodiment ofthe disk driving device according to the invention; and

[0035]FIG. 10 is a bottom view of the device illustrated in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Now the present invention will be explained in detail withreference to the drawings.

[0037]FIG. 1 is a half cross sectional and half front view of a diskdriving device of an embodiment of the optical information recordingand/or reproducing apparatus according to the invention. In the presentembodiment, a magneto-optical disk installed within a cartridge issupported by a turntable formed by a spindle cup and is rotated by aspindle motor. FIG. 2 shows an optical head and a focus control systemof the present embodiment.

[0038] As shown in FIG. 1, the disk driving device comprises a main body201 and a spindle motor 204 which is arranged above the main bodymovably up and down by means of an up-down block 273. That is to say,the spindle motor 204 is secured to the up-down block 273 which isarranged movably up and down. On a driving shaft 288 of the spindlemotor 204, a spindle cup 275 is arranged slidably along the drivingshaft, but is rotated together with the driving shaft 288. To this end,a key 287 extending in an axial direction of the driving shaft 288 issecured to the driving shaft and this key is slidably inserted into arecess formed in an inner wall of the spindle cup 275. An upper surfaceof the spindle cup 275 forms a turntable 241 for the optical disk aswill be explained later.

[0039] To an upper portion of the spindle motor 204 is secured aring-shaped electromagnet 271, and a ring-shaped permanent magnet 272 issecured to a bottom surface of the spindle cup 275 such that they arefaced with each other. As will be explained later, the permanent magnet272 is rotated by the spindle motor 204 and the electromagnet 271 issometimes brought into contact with the rotating permanent magnet 272.In order to prevent the electromagnet 271 from being damaged by saidsliding contact, the electromagnet is covered with a plastic housing.

[0040] In the up-down block 273, there are formed through holes 273 aextending in parallel with an axial direction of the driving shaft ofthe spindle motor 204, and guide shafts 274 secured to the main body 201are inserted into the through holes such that the up-down block 273 issmoothly moved up and down along the guide shafts 274. The up-down block273 extends in the axial direction such that it substantially surroundsthe spindle cup 275 and includes at least three projections 276. Whenthe up-down block 273 is driven into an upper position, round front endsof the projections 276 are brought into contact with a round edge of arecess formed in a lower surface of the cartridge 251, so that thecartridge is positioned with respect to the up-down block 273 and thusthe driving shaft 288 of the spindle motor 204. It should be noted thattips of these projections 273 a situate on a plane which isperpendicular to the axial direction of the driving shaft 288.

[0041] To a side wall of the up-down block 273 is secured a rack gear278 which engages with a pinion gear 279, and this pinion gear 279 isdriven by an up-down motor 280 arranged on the main body 201. Therefore,by driving the up-down motor 280, it is possible to move the up-downblock 273 and thus the spindle motor 204 up and down. Between the mainbody 201 and the lower surface of the up-down block 272 at the guideshafts 274, there are arranged compressing coiled springs 281 such thatthe up-down block is biased to move upward.

[0042] On a lower surface of the spindle motor 204 there is secured alight reflecting member 282 by an adhesive agent. The light reflectingmember 282 comprises a glass plate on which a metal thin film is coated.The glass plate may be formed in a wedge-shaped one. On the main body201 there is secured a photoreflector 283 by an adhesive agent at aposition corresponding to the reflecting member 282. The photoreflector283 is well known in the art and may be formed by a unit including alight emitting diode and two light receiving regions.

[0043] The magneto-optical disk 242 installed within the cartridge 251has a disk hub 277 made of magnetic material secured to a central holeof the disk by means of an adhesive agent. To the spindle cup 275 issecured a ring-shaped magnetic yoke 284 and a ring-shaped permanentmagnet 285 is secured to the yoke. Therefore, when the spindle cup 275is moved upward and a distance between the yoke 284 and the magnetic hub277 of the disk 242 becomes smaller than a given value, the disk hub 277is attracted by the yoke 284 as illustrated in FIG. 1. In this manner,according to this embodiment, when the up-down block 273 is moved upwardby means of the up-down motor 280, the positioning of the disk 242 withrespect to the axis of the spindle cup 275 can be obtained and at thesame time the magneto-optical disk 242 is firmly coupled with thespindle cup.

[0044] In the present embodiment, the up-down block 273 having thespindle motor 204 secured thereto and the spindle cup 275 can be movedup and down independently from each other. That is to say, the spindlecup 275 is coupled with the driving shaft 288 of the spindle motor 204such that the spindle cup can be moved up and down with respect to thedriving shaft by supplying a driving current to the electromagnet 271.Therefore, the focus search and focus servo can be performed withoutmoving the up-down block 273. On the other hand, the spindle cup 275 hasto be rotated by the spindle motor 204, so that the spindle cup iscoupled with the driving shaft of the spindle motor 204 by means of akey and recess coupling mechanism. That is to say, a key 289 extendingin the axial direction of the driving shaft 288 is secured to thedriving shaft, and a recess is formed in a side wall of the spindle cup275, said key being inserted into the recess.

[0045] In the present embodiment, there are provided the first drivingmechanism (278, 279, 280) for moving the up-down block 273, i.e. thespindle motor 204 in the up and down directions with respect to thespindle cup 275 and the second driving mechanism (271, 272) for movingthe spindle cup 275 in the up and down directions with respect to thespindle motor 204.

[0046] To the driving shaft of the spindle motor 204 is secured astopper 286, and between the stopper 286 and the spindle cup 275 isarranged a coiled spring 287 for biasing the spindle cup downward.Therefore, when the electromagnet 271 is not energized, the spindle cup275 is driven to the lower position so that the permanent magnet 27 isbrought into contact with the electromagnet 271.

[0047] As illustrated in FIG. 2, the optical pick-up apparatus comprisesa stational optical unit 202 and an objective lens driving unit 203,these units being arranged on the main body 201. The stational opticalunit 233 comprises semiconductor laser 221, collimator lens 222, prism230 having first and second beam splitters 231 and 232, half wavelengthplate 261, collecting lens 262, polarizing beam splitter 263 and firstand second photodetectors 224 and 264. The objective lend driving unit203 comprises a carriage 233, reflection prism 332 and objective lens333. The carriage 233 is arranged movably in a radial direction of themagneto-optical disk 242 by means of a suitable driving mechanism suchas a linear motor not shown. A laser beam emitted by the semiconductorlaser 221 is converted into a parallel beam by means of the collimatorlens 222 and is then made incident upon the first beam beam splitter231. A laser beam reflected by the first beam splitter 231 is receivedby the first photodetector 224 and an output signal of the firstphotodetector is supplied to an automatic power control circuit (APC)225 which controls the output power of the semiconductor laser 221 inaccordance with the output signal from the first photodetector 224.

[0048] The output signal of the first photodetector 224 is also suppliedto a control device (CPU) 207 of a focus control system. The focuscontrol system includes in addition to this CPU 207 focus drivingcircuit 206 and switch SW. In order to initiate the focus search orfocus control, to the control device 207 are supplied a detection signalof the rotation of the magneto-optical disk 242 and a detection signalof the up-down movement of the spindle motor 204. That is to say, anoutput signal SPDP of the photoreflector 283 and an output signal of anencoder (not shown) fro detecting the rotation of the spindle motor 204are supplied to the control device 207. The switch SW is controlled bythe control device 207 in accordance with these output signals. Theabove mentioned electromagnet 271 is connected to the driving circuit206.

[0049] A laser beam transmitted through the first beam splitter 231 isthen made incident upon the second beam splitter 232 and a laser beamtransmitted through the second beam splitter 232 emanates from thestational optical unit 202 toward the objective lens driving unit 203.

[0050] Now the carriage 233 of the objective lens driving unit 203 willbe explained in detail.

[0051]FIGS. 3 and 4 are plan and exploded perspective views,respectively showing the carriage 233. The carriage 233 is arranged on aslide guide 233A comprising movable member 341, elongated stationarymember 342 secured to the main body 201 and retainer 343 and is movedalong the slide guide in the radial direction of the magneto-opticaldisk 242.

[0052] A carriage main body 233B is formed by a plate-like member, andthis plate-like member is inserted between upper and lower coil portions337U and 337D of an access coil 377 and is secured to the access coil.That is to say, lower and upper surfaces 233 a and 233 b of theplate-like member 233B are cemented to the lower and upper coil portions337D and 377U, respectively by means of an adhesive agent.

[0053] The reflecting prism 332 of the objective lens driving unit 203is mounted on a projection 233 c of the carriage main body 233B and issecured thereto by cementing. The objective lens 333 is supported by alens holder 344 in the form of a box having openings, and the reflectingprism 332 and projection 233 c are inserted into the lens holder throughone opening such that the reflecting prism 332 faces the objective lens333.

[0054] A projection 233 d of the carriage main body 233B is insertedinto a recess 344 a formed in a supporting block 344 and is securedthereto by an adhesive agent. In this manner, the supporting block 344is fixed to the carriage main body 233B.

[0055] In a lower surface of the supporting block 344 there is formed adepression 344 b into which the movable member 341 can extend. In thesupporting block 344 there is further formed a through hole 344 c forpassing the laser beam. Surfaces of side projections 344 d and 344 eformed in the upper and lower surfaces of the supporting block 334 aresecured to a base portion of a leaf spring unit 336 by cementing. Theleaf spring unit 336 comprises four leaf springs 336 a to 336 d whosefree ends are secured to the lens holder 334. In this manner, the lensholder 334 and thus the objective lens 333 can be supported to beresiliently moved at least in a focusing direction parallel with anoptical axis of the objective lens 333 as well as a tracking directionperpendicular both to the optical axis and an information track on themagneto-optical disk 242.

[0056] On the lens holder 334 there are wound tracking coils 335 whichare inserted into spaces 337 b formed between permanent magnets 338 andinner yokes 340 which constitute a magnetic circuit of the linear motortogether with outer yokes 339. The access coil 337 is arranged tosurround or embrace the inner yokes 340, so that the movable portionincluding the access coil 337, carriage main body 233B, supporting block344 and lens holder 334 is moved linearly along the slide guide 233A bysupplying a current to the access coil.

[0057] As explained above the front ends of the leaf springs 336 a to336 d are secured to the lens holder 334. The leaf springs 336 a to 336d have expanding and shrinking portions 336 e to 336 h, respectively,each of which is formed by a mesh woven from very fine wires and arubber coating applied on the mesh. When the lens holder 334 is moved inthe tracking direction, the expanding and shrinking portions 336 e to336 h are deformed in a plane of the drawing of FIG. 3. Further, thelens holder 334 can be moved in the radial direction of themagneto-optical disk 242 even if the carriage main portion 233B isstationary.

[0058] The carriage main body 233B is guided along the slide guide 233Aby means of an intermediate member 345. That is to say, upper surfaces345 a of upper projections of the intermediate member 345 are cementedonto the lower surface of the carriage main body 233B such that theportion 337U of the access coil 377 is clamped between the intermediatemember and the carriage main body, and further the movable member 341 isclamped into a recess 345 b formed in the lower surface of theintermediate member 345 and is cemented thereto by a suitable adhesiveagent.

[0059] The permanent magnets 338 and outer and inner yokes 339 and 340are secured to the main body 201 and the outer and inner yokes arecoupled with each other at their ends to form the closes magneticcircuits. It should be noted that sizes of the lens holder 344, accesscoil 337, permanent magnet 338 and yokes 339, 340 are so determined thatthe smooth movement of the carriage main body 233B is not affected.

[0060] When the current is supplied to the access coil 337, the carriagemain body 233B is moved together with the movable portion 341 in theradial direction of the magneto-optical disk 242 along the slide guide233A. Further the tracking control can be performed by supplying thetracking control signal to the tracking coils 335. That is to say, thetracking coils 335 cooperate with the magnetic field formed by thepermanent magnets 338 and yokes 339, 340 to move the carriage main body233B, i.e. the lens holder 334 in the radial direction of the disk 242.In this manner, according to the invention, the magnetic circuitcomposed of the permanent magnets 338 and yokes 339, 340 is utilizedboth for the linear movement of the carriage main body 233B and thetracking control. Furthermore, according to the invention, the focussearch and focus control are performed not by moving the objective lens333 in the direction of its optical axis, but by moving themagneto-optical disk 242 by means of the electromagnet 271 and permanentmagnet 272. Therefore, it is not necessary to provide the focusingmechanism including the permanent magnet and focusing coil in the lensholder, so that the objective lens driving device 203 can be furthermade small in size and light in weight and can be manufactured easily ina less expensive manner.

[0061] The parallel laser beam emanating from the stationary unit 202 ismade incident upon the reflecting prism 332 and is reflected therebyupwardly and is made incident upon the objective lens 333. The laserbeam is then made incident upon the magneto-optical disk 242. The returnlaser beam reflected by the magneto optical disk 242 is made incidentupon the stationary unit 202 by means of the objective lens 333 andreflecting prism 332.

[0062] The return laser beam is reflected by the second beam splitter232 in the optical system 260 and is made incident upon the halfwavelength plate 261 so that its polarizing direction is rotated by 45degrees. Then the return beam is made incident upon the polarizing beamsplitter 263 by means of the collecting lens 262. The polarizing beamsplitter 263 serves as the analyzer and P-polarized component istransmitted through the polarizing beam splitting plane and S-polarizedcomponent is reflected by the polarizing beam splitting plane, and theseP-polarized and S-polarized components are received by separate lightreceiving elements of the photodetector 264.

[0063] By suitably processing outputs of the light receiving elements ofthe photodetector 264, it is possible to derive a focusing error signalrepresenting a deviation of the focuses spot of the beam with respect tothe information record plane of the magneto-optical disk 242 in thedirection of the optical axis, a tracking error signal denoting adeviation of the focus point of the beam with respect to the informationtrack in the radial direction, and an information signal representingthe information recorded on the magneto-optical disk.

[0064] As shown in FIG. 2, there is provided a magnetic head 205 abovethe disk 242 and the magnetic head is secured to a supporting arm notshown. The supporting arm is driven such that the magnetic head 205 isalways indexed into a position facing the objective lens driving unit203 via the disk 242.

[0065] The focusing error signal is supplied to a focus control circuit206 by means of the switch SW controlled by the control device 207. Thefocus control circuit 206 comprises focus servo control circuit (FOD)206 a and focus search control circuit (FOS) 206 b. Output terminals ofthe focus servo control circuit 206 a and focus search control circuit206 b are connected to a coil L of the electromagnet 271 arranged on thespindle motor 204. By supplying a control signal having a suitablepolarity to the coil L from the focus control circuit 206, theelectromagnet 271 generates a magnetic field having a given direction toproduce the repelling force in combination with the permanent magnet272, so that the spindle cup 275 on which the disk 242 is mounted ismoved upward against the spring force of the coiled spring 287 and themagneto-optical disk 242 is moved away from the objective lens 333. Inthis manner, by changing the magnitude of the control signal, thedistance between the disk 242 and the objective lens 333 can be adjustedin combination of the repelling force produced by the electromagnet 271and permanent magnet 272 and the resilient force of the coiled spring287.

[0066] In the present embodiment, the control device 207 controls notonly the focus control system but also other control systems. Forinstance, the spindle motor 204, up-down motor 280, linear motor fordriving the objective lens driving unit 203, semiconductor laser 221,and tracking coils 335 may be controlled by the control device 207.

[0067] Now the operation of the present embodiment will be explainedalso with reference to a flow chart illustrated in FIG. 5.

[0068] In FIG. 1, above the main body 201, there is arranged a cartridgeholder (not shown). At first, the cartridge 251 is inserted into thecartridge holder. The cartridge holder and a mechanism for mounting thecartridge are well known in the art, so that they are not explainedfurther in detail. For instance, the known cartridge holder disclosed inthe above mentioned Japanese Patent Application Laid-open PublicationKokai Hei 4-351785 may be used. This known cartridge holder has openingsat front and rear sides and the disk is rotatably installed within acartridge.

[0069] The cartridge holder is constructed such that the cartridge 251can be inserted in parallel with the main body 201. That is to say, whenthe cartridge 251 is inserted into the cartridge holder, a shutteropening pin on the cartridge holder pushes a shutter of the cartridge251 in accordance with the movement of the cartridge, and thus anopening of the cartridge on the recording and reproducing side isopened. At the same time, the cartridge 251 is inserted into a spacebetween the objective lens driving unit 203 and the magnetic head 205.

[0070] When the cartridge 251 has been inserted upto a given completeinserting position, this is detected by a detector not shown and itsdetection signal is supplied to the control device 207. Then, thecontrol device 207 controls the up-down motor 280, so that the up-downblock 273 is moved upward from a lower home position by means of thepinion gear 279 and rack gear 278. When the up-down block 273 is movedupward and comes close to the cartridge 251, the projections 276 of theup-down block 273 are brought into contact with the positioning recessformed in the lower surface of the cartridge 251. At the same time orafter that, the hub 277 of the disk 242 is attracted onto the turntable241 of the spindle cup 275 by the attracting force produced by thepermanent magnet 285.

[0071] When no current is supplied to the coil L of the electromagnet271, the electromagnets 271 and permanent magnet 272 are brought intocontact with each other by means of the spring force of the coiledspring 287. The electromagnet 271 and permanent magnet 272 aredetermined such that under said condition there is still formed anecessary space between the lower surface of the cartridge 251 and thedisk 242.

[0072] During the upward movement of the up-down block 273, the positionof the up-down block 273 is detected by the photoreflector 283. That isto say, the photoreflector 283 projects the light beam toward thereflecting member 282 and the reflected light beam is made incident uponthe photoreflector. A position of the reflected light beam spot on thetwo light receiving regions of the photoreflector 283 is changed inaccordance with the distance from the photoreflector and the reflectingmember 282. Therefore, this distance can be detected by deriving adifference between outputs of these light receiving regions 283 a of thephotoreflector 283. The thus detected distance SPDP is supplied to thecontrol device 207.

[0073] When it is confirmed that the up-down block 273 has moved intothe given upper position from the output signal of the photoreflector283, the spindle motor 204 is energized and the disk 242 is rotatedtogether with the spindle cup 275. To the driving shaft 288 of thespindle motor 204 is secured a rotary encoder 291 shown in FIG. 2 andthe output signal SPFD of the rotary encoder is converted by a F/V(frequency/voltage) and the converted voltage is applied to the controldevice 207.

[0074] Before rotating the disk 242, the carriage 233 is moved into theinner most position of the disk. After it is confirmed that the disk hasbeen rotated at a given constant speed such as 3600 rpm, the controldevice 207 energizes the semiconductor laser 221 to emit the laser beam.When the semiconductor laser 221 emits the laser beam, this is detectedby the first photodetector 224 and the thus detected signal is suppliedto the control device 207. Then, the control device 207 confirms thatthe laser beam having a give intensity has been emitted from thesemiconductor laser 221.

[0075] In the manner explained above, after confirming that the spindlemotor 204 and spindle cup 275 have been moved into the upper position,the disk 242 has been rotated at the given speed, and the semiconductorlaser 221 has emitted the laser beam having the given intensity, thecontrol device 207 initiates the focus control. That is to say, at firstthe focus search control is effected by supplying the focus searchsignal from the focus search control circuit 206 b to the coil L of theelectromagnet 271 under the control of the control device 207. The focussearch control itself is well known in the art, so that this will beexplained only briefly. In the present embodiment, in the initialcondition, the disk 242 is in the nearest position to the objective lens333, so that usually the focus point of the laser beam situates abovethe disk 242. When the focus search control is initiated, the spindlecup 275 is gradually moved upward so that the disk 242 is moved awayfrom the objective lens 333. During this period, the focusing errorsignal generated by the photodetector 264 is supplied to the focussearch control circuit 206 b via the switch SW and this focusing errorsignal is compared with a predetermined threshold level. When thefocusing error signal exceeds the threshold level, it can be confirmedthat the disk 242 has been driven into the dynamic range of the focusservo. Then, the focus search is finished and the focus servo isinitiated by the focus servo control circuit 206 a. That is to say, thecontrol signal supplied to the focus control coil L is changed inaccordance with the focusing error signal supplied from thephotodetector 264 such that the laser beam spot is always focused on theinformation record plane of the disk 242.

[0076] As explained above, in the present embodiment, after the controldevice 207 has confirmed that the spindle motor 204 and spindle cup 275have been moved into the upper position and the revolving speed of thespindle motor 204 has increased to the predetermined value, and thesemiconductor laser 221 has emitted the laser beam having thepredetermined intensity, the control device 207 allows the focus searchcontrol and focus servo control.

[0077] Therefore, according to the invention, the focus search controland focus servo control are not performed when the up-down block 201 ismoving and the disk 242 is not rotated at a given revolving speed, sothat the reliability of the apparatus is improved and noise due tomalfunction can be avoided.

[0078] Furthermore, after the objective lens driving unit 203 has beenmoved into the innermost position, the disk is rotated. Therefore, apossibility that the disk might be brought into contact with theobjective lens driving unit 203 can be minimum, because the disk ishardly bent at the innermost position. Therefore, the focus searchcontrol can be stably and promptly performed.

[0079] As stated above, the focus search and focus servo control can becarried out by supplying the current to the coil L of the electromagnet271. When the control device 207 allows the initiation of the control ofthe focus, at first the focus search signal is supplied to the coil L ofthe electromagnet 271 and there is produced a repelling force betweenthe electromagnet 271 and the permanent magnet 272, so that the spindlecup 275 and thus the disk 242 is moved upward against the force of thecoiled spring 287. During this movement, the focusing error signal issupplied to the focus search control circuit 206 b via the switch SW.Therefore, the disk 242 is moved into the dynamic range of the focusservo, and then the focus servo control is initiated. In this case, thefocus servo control signal may be superimposed on the focus searchcontrol signal at the end of the focus search control. Then, the focussearch control can be smoothly and stably transferred to the focus servocontrol without being affected by the inertia of the movable portionincluding the disk 242 and spindle cup 275. After that, the focusingerror signal detected by the photodetector 264 is supplied to the focuscontrol circuit 206 a via the switch SW and the disk 242 is moved up anddown in accordance with the focusing error signal.

[0080] In this manner, in the present embodiment, the spindle cup 275constituting the turntable 241 for the disk 242 can be independentlymoved in the axial direction with respect to the up-down block 273 andthe focus search control and focus servo control are performed by movingonly the spindle cup 275. In other words, the focus search control andfocus servo control can be effected without moving the up-down block 273having a large weight. Moreover, the objective lens driving unit 203does not include a permanent magnet for driving the objective lens 333in the focusing direction, and thus the objective lens driving unit canbe made small in size and light in weight and the high speed access canbe attained.

[0081] Further, in the present embodiment, the cartridge 251 is stablysupported during the focus search control, so that some members of thecartridge supporting mechanism are not brought into contact with eachother and the generation of noise can be effectively avoided. In thismanner, noise can be removed and the reliability is increased, while theadvantages of the known apparatuses can be still attained.

[0082]FIGS. 6 and 7 show another embodiment of the disk driving deviceof the optical information recording and/or reproducing apparatusaccording to the invention. In the present embodiment, the up and downmovement of the spindle motor and spindle cup is carried out by means ofa swingable movement of a plate like member. The disk driving devicecomprises a base member 11 having a flat upper surface and a drivingplate 12 arranged on the upper surface of the base member 11 such thatthe driving plate can slide thereon in a direction A. On the base member11 there are provided a plurality of pins 13 and these pins are insertedinto recesses 14 formed in the driving plate 12 (in FIG. 6, only one ofpins and one of recesses are seen). On the base member 11 there are alsosecured pins 15 and coiled springs 16 are arrange between the pins 15and a left hand projection 12 a of the driving plate 12, so that thedriving plate is biased to be moved in the leftward direction. Thedriving plate 12 further comprises an operating portion 12 b at itsright hand end, said operating portion being gradually bent upwardly.

[0083] To both sides of the base member 11 there are secured uprightprojections 17 and a shaft 18 is supported by these projections suchthat the shaft extends horizontally. To the shaft 18, there is swingablysecured a supporting plate 19. The supporting plate 18 is biased by acoiled spring 20 to be rotated in the clockwise direction about theshaft 18. On the supporting plate 19 there is secured an up-down block21 to which a spindle motor is secured. Between the supporting plate 19and the up-down block 21, there are arranged rubber rings 22 serving ascushion. Similar to the first embodiment, the spindle motor secured tothe up-down block 21 includes a driving shaft and a spindle cup 23 isarranged slidably along the driving shaft. On the up-down block 21,there are arranged projections 24 for positioning a cartridge 25 havinga magneto-optical information record disk 26. The disk 26 is firmlyplaced on a turntable formed by the spindle cup 23 by means of themagnetic force.

[0084] In the present embodiment, in a right hand end of the supportingplate 19, there is provided a light emitting diode (LED) 27 and a lightbeam emitted by the LED is projected downward through a stop 28 having afine hole. In the operating portion 12 b of the driving plate 12, thereis formed an opening 29, and on the base member there is provided aphotodetector 30. FIG. 6 shows a condition in which the cartridge 25 hasbeen fully inserted, the driving plate 11 is moved into the left handposition, and an assembly of the up-down block 21, the spindle motor andspindle cup 23 is moved into an upper position so that the cartridge 25is positioned by the projections 24 with respect to the spindle cup andthe disk 26 is placed on the turntable of the spindle cup. In thiscondition, the light beam emitted by the LED 27 is transmitted throughthe opening 29 formed in the operating portion 12 b of the driving plate12 and is made incident upon the photodetector 30.

[0085]FIG. 7 illustrates a condition in which the cartridge 25 isremoved and the driving plate 12 is moved into the right hand position,so that the supporting plate 19 is rotated in the clockwise directionabout the shaft 18. Therefore, the projections 24 are removed from thecartridge 25 and the spindle cup 23 is removed from the disk. In thiscondition, the light beam emitted from the LED 27 is shielded by thedriving plate 12, and thus the light beam is not made incident upon thephotodetector 30. In the manner explained above, in the presentembodiment, the position of the spindle motor 21 and spindle cup 23 canbe directly detected by monitoring an output signal of the photodetector30.

[0086]FIG. 8 illustrates a modification of the embodiment shown in FIGS.6 and 7, so that portions in FIG. 8 which are similar to those depictedin FIGS. 6 and 7 are denoted by the same reference numerals used inFIGS. 6 and 7. In the present embodiment, a photoreflector 31 isarranged on the spindle motor 21 such that a light beam reflected by thecartridge 25 can be received by light receiving regions of thephotoreflector. In the present embodiment, by monitoring an outputsignal from the photoreflector 30, it is possible to detect theinsertion of the cartridge 25 into the apparatus. When the insertion ofthe cartridge 25 is detected, a trigger lever not shown is driven tomove the driving plate 12 in the left hand direction by means of theaction of the springs 16. Then, the right hand edge of the supportingplate 19 slides on the operating portion 12 b of the driving plate 12,and thus the supporting plate 19 is rotated in the anti-clockwisedirection. Therefore, the cartridge 25 is supported by the projections24 and the disk 26 is placed on the spindle cup 23. This can be alsodetected by the output signal of the photoreflector 30. Then, thespindle motor secured to the up-down block 21 is energized to rotate thedisk 26 up to a predetermined revolving speed, and after that the focuscontrol is initiated.

[0087] In the present embodiment, the photoreflector 30 can detect notonly the upward movement of the up-down block 21, spindle motor andspindle cup 23, but also the insertion of the cartridge 25.

[0088]FIGS. 9 and 10 illustrate still another embodiment of the diskdriving device of the optical recording and/or reproducing apparatusaccording to the invention. In the present invention, the rotatingmovement is transferred into the up-down movement by means of aninclined recess and a pin. The disk driving device comprises a basemember 41 on which a ring-shaped support member 42 is secured by meansof screws 43. On the supporting member 42, there is arranged a rotatingcylinder 44 and a clamping ring 45 having a thread formed in its innersurface. That is to say, the supporting ring 42 is clamped between therotating cylinder 44 and the clamping ring 45 such that the rotatingcylinder 44 is rotated about its longitudinal axis together with theclamping ring 45, but could not move in the axial direction. On an outersurface of the rotating cylinder 44, is secured a arcuate rack gear 46which is engaged with a warm gear 47 coupled with a driving shaft of anup-down motor 48. Therefore, by driving the up-down motor 48, it ispossible to rotate the rotating cylinder 44 about the longitudinal axialdirection thereof. On the outer surface of the rotating cylinder 44,there is also secured a light shielding plate 49, and a photointerruptoris arranged on the base member 41 such that the light shielding plate 49is arranged between a light emitting diode 50 and a photodetector 51.

[0089] Within the rotating cylinder 44 is arranged an up-down block 52having secured a spindle motor and a spindle cup 53. The construction ofthe up-down block 52 with projections 53, spindle motor and spindle cup54 is substantially same as that of the first embodiment shown inFIG. 1. In FIG. 9, the spindle motor is not seen and only an upperportion of the spindle cup 54 is seen. In the side wall of the rotatingcylinder 44, there is formed an inclined recess 55 and on the up-downblock 52 there is secured a pin 56 which is inserted into the recess 55.Therefore, by rotating the rotating cylinder 44 by means of the motor48, the up-down block 52 is moved up and down. It should be noted thatthe spindle cup 54 can be moved up and down with respect to the spindlemotor and up-down block 52 by means of the magnetic driving mechanismincluding the electromagnet 271 and permanent magnet 272 shown in FIG.1.

[0090]FIG. 10 shows a bottom of the disk driving device. In order toprevent the up-down block 52 from being rotated together with therotating cylinder 44, in the outer surface of the up-down block, thereis formed a recess 57 extending in its axial direction and a guide plate58 is inserted into the recess 57 such that the up-down block 52 can bemoved up and down. In the lower edge of the rotating cylinder 44, thereis formed a recess 59, so that the rotation of the rotating cylinder 44can rotate without being prevented by the guide plate 58.

[0091] In the present embodiment, when the cartridge is not fullyinserted, the rotating cylinder 44 is in a home position at which theup-down block 52 is in a lower position P1. After the cartridge isinserted into the apparatus, the up-down motor 48 is energized to rotatethe rotating cylinder 44. Then, the up-down block 52 is moved upwardinto an upper position P2. In the upper-position P2, a cartridge issupported by the projections 53 and a disk is placed on a turntableformed by the spindle cup 54. During the rotation of the rotatingcylinder 44, the light shielding plate 49 is existent between the lightemitting diode 50 and the photodetector 51, and thus a light beam is notmade incident upon the photodetector 51. When the up-down block 52 isdriven into the upper position P2, the light shielding plate 49 is nomore existent between the light emitting diode 50 and the photodetector51, so that the light beam is made incident upon the photodetector.Therefore, by monitoring the output signal from the photodetector 51, itis possible to detect the position of the up-down block 52. After it isconfirmed that that the up-down block 52 has been driven into the upperposition P2, the spindle motor is energized, and then after it isconfirmed that the disk has been rotated at a given speed, the focuscontrol is initiated.

[0092] The present invention is not limited to the above explainedembodiments, but many modifications and alternations may be conceived bythose skilled in the art within the scope of the invention. Forinstance, in the above mentioned embodiments, the focus controlincluding the focus search control and focus servo control are performedby moving the optical information record disk while the objective lensis remained stationary in the focusing direction, but according to theinvention the focus control may be carried out by moving the objectivelens in a direction of its optical axis.

What is claimed is:
 1. An apparatus for recording and/or reproducinginformation on and/or from an optical record disk comprising: an opticalhead including a semiconductor laser for emitting a laser beam, anobjective lens for projecting the laser beam emitted by thesemiconductor laser onto the optical information record disk and aphotodetecting means for receiving a return laser beam reflected by saidoptical information record disk to produce information signal andfocusing error signal; a disk driving means including an up-down blockarranged movably in a direction perpendicular to a plane of the opticalinformation record disk between a lower position and an upper position,an up-down motor for moving said up-down block between said lowerposition and upper position, a turntable for supporting the opticalinformation record disk and a spindle motor secured to said up-downblock and having a driving shaft coupled with said turntable forrotating the turntable together with the optical information recorddisk; an optical head driving means for driving at least said objectivelens in a radial direction of the optical information record disk; aposition detecting means for detecting directly a position of saidup-down block to derive a position signal when the up-down block isdriven into said upper position; a rotation detecting means fordetecting a rotation of said optical information record disk to derive arotation signal when the optical information record disk is rotated at apredetermined revolving speed; and a control means for initiating afocus control for moving said objective lens and turntable relative toeach other in accordance with said position signal and rotation signal.2. An apparatus according to claim 1, wherein said turntable of saiddriving means is formed by an upper surface of a spindle cup which isarranged on the driving shaft of said spindle motor such that theturntable is rotated together with the driving shaft of spindle motorbut is slidable along the driving shaft, and said disk driving meanscomprises a turntable driving device for moving said turntable up anddown along the driving shaft of the spindle motor.
 3. An apparatusaccording to claim 2, wherein said turntable driving device of the diskdriving means comprises an electromagnet secured to said spindle motor,a permanent magnet secured to said spindle cup such that theelectromagnet and permanent magnet face with each other, and a springarranged between said driving shaft and said spindle cup such that thespindle cup is biased to move away from the optical information recorddisk.
 4. An apparatus according to claim 2, wherein said opticalinformation record disk is rotatably installed within a cartridge andsaid up-down block comprises at least three positioning projectionswhich are urged against a lower surface of the cartridge when saidup-down block is driven into said upper position to position thecartridge with respect to the driving shaft of the spindle motor.
 5. Anapparatus according to claim 1, wherein said position detecting meanscomprises a photoreflector which is secured to a base member on whichsaid up-down block is arranged movably up and down and includes a lightsource for emitting a light beam and a photodetector, and a reflectingmember secured to a lower surface of the up-down block at such aposition that said light beam is made incident upon the reflectingmember and is reflected by the reflecting member toward thephotodetector of the photoreflector.
 6. An apparatus according to claim1, wherein said disk driving means comprises a rack secured to saidup-down block and a pinion which is coupled with said up-down motor andis engaged with said rack.
 7. An apparatus for recording and/orreproducing information on and/or from an optical record diskcomprising: an optical head including a semiconductor laser for emittinga laser beam, an objective lens for projecting the laser beam emitted bythe semiconductor laser onto the optical information record disk and aphotodetecting means for receiving a return laser beam reflected by saidoptical information record disk to produce information signal andfocusing error signal; a disk driving means including an up-down blockarranged movably in a direction perpendicular to a plane of the opticalinformation record disk between a lower position and an upper position,an up-down motor for moving said up-down block between said lowerposition and upper position, a turntable for supporting the opticalinformation record disk and a spindle motor secured to said up-downblock and having a driving shaft coupled with said turntable forrotating the turntable together with the optical information recorddisk; an optical head driving means for driving at least said objectivelens in a radial direction of the optical information record disk; aposition detecting means for detecting directly a position of saidup-down block to derive a position signal when the up-down block isdriven into said upper position; a control means for initiating anenergization of said spindle motor for rotating the optical informationrecord disk in accordance with said position signal.
 8. An apparatusaccording to claim 7, wherein said turntable of said driving means isformed by an upper surface of a spindle cup which is arranged on thedriving shaft of said spindle motor such that the turntable is rotatedtogether with the driving shaft of spindle motor but is slidable alongthe driving shaft, and said disk driving means comprises a turntabledriving device for moving said turntable up and down along the drivingshaft of the spindle motor.
 9. An apparatus according to claim 8,wherein said disk driving means comprises a rack secured to said updownblock and a pinion which is coupled with said updown motor and isengaged with said rack.
 10. An apparatus according to claim 8, whereinsaid disk driving means comprises a driving plate arranged on a basemember slidably in a plane parallel with the optical information recorddisk between first and second positions and having at one end thereof anoperating portion which is gradually ascended toward the opticalinformation record disk, and a supporting plate on which the spindlemotor is secured and which is arranged swingably about a shaft whichextends in parallel with the optical information record disk betweenfirst and second positions; whereby when said driving plate is driveninto the first position, the supporting plate is driven into the firstposition at which said up-down block is driven into the lower positionand when said driving plate is driven into the second position, saidsupporting plate is driven into the second position at which saidup-down block is driven into the upper position.
 11. An apparatusaccording to claim 10, wherein said position detecting means comprises alight source for emitting a light beam and secured to one of said basemember and supporting plate, a photodetector for receiving the lightbeam emitted by said light source and secured to the other of said basemember and supporting plate, and an opening formed in said driving plateat such a position that when said driving plate is in the secondposition, the light beam is made incident upon the photodetector viasaid opening.
 12. An apparatus according to claim 10, wherein saidposition detecting means comprises a photoreflector secured to saidup-down block and including a light source for emitting a light beamtoward the optical information record disk or a cartridge having theoptical information record disk installed therein, and a photodetectorfor receiving the light beam emitted by said light source and reflectedby said optical information record disk or said cartridge.
 13. Anapparatus according to claim 8, wherein said disk driving meanscomprises a rotating cylinder arranged rotatably on a base memberbetween first and second positions, a rack gear secured onto a side wallof the rotating cylinder, a warm gear engaged with said rack gear andcoupled with a driving shaft of said up-down motor, a recess formed inthe side wall of the rotating cylinder and being inclined with respectto an axial direction of the rotating cylinder, a pin secured to saidup-down block and inserted into said recess such that when the rotatingcylinder is rotated by said up-down motor by means of the warm gear andrack gear between said first and second positions, the up-down block ismoved between said lower and upper positions.
 14. An apparatus accordingto claim 13, wherein said position detecting means comprises aphotointerruptor arranged on said base member and having a light sourcefor emitting a light beam and a photodetector for receiving the lightbeam emitted by the light source, and a light shielding plate secured onthe side wall of said rotating cylinder such that the light shieldingplate is positioned between the light source and the photodetector;whereby when said rotating cylinder is not in said second position, thelight shielding plate is existent between said light source andphotodetector, but when said rotating cylinder is driven into saidsecond position, the light beam emitted by the light source is madeincident upon the photodetector without being interrupted by said lightshielding plate.